The effect of age and sex on peak oxygen uptake during upper and lower body exercise: A systematic review.

BACKGROUND: Large scale population norms for peak oxygen uptake (VO2peak) during cycle ergometry (CE) have been published for men and women across a wide range of ages. Although upper body functional capacity has an important role in activities of daily living far less is known regarding the effect of age and sex on upper body functional capacity (i.e. arm crank ergometry; ACE). The aim of this review was to determine the effect of age and sex on VO2peak obtained during ACE and CE in the same participants. METHOD: The review was pre-registered with PROSEPERO (Ref: CRD42022349566). A database search using Academic Search Complete including CINAHL complete, CINHAL Ultimate, Medline, PubMed, SPORTDiscus was undertaken. RESULTS: The initial search yielded 460 articles which was reduced to 243 articles following removal of duplicates. Twenty-five articles were subsequently excluded based on title resulting in 218 articles considered for retrieval. Following review of the abstracts, 78 further articles were excluded leaving 140 to be assessed for eligibility. Eighty-five articles were subsequently excluded, resulting in 55 articles being included. The decrease in VO2peak with age during CE was consistent with previous studies. Decreases in VO2peak during ACE with age, although paralleling those of CE, appeared to be of greater functional importance. When changes in VO2peak were considered below the age of 50 years little change was observed for absolute VO2peak during ACE and CE. In contrast, relative VO2peak demonstrated decreases in VO2peak for both ACE and CE likely reflecting increases in body mass and body fat percentage with age. After 50 years of age absolute and relative VO2peak demonstrated more similar and subtle responses. Heterogeneity across studies for both absolute and relative VO2peak between ACE and CE was large. Although strict inclusion criteria were applied, the inter-individual variation in sample populations was likely the main source of heterogeneity. There was a considerable lack data sets available for ages above 40 years of age. CONCLUSIONS: These responses suggest that upper body VO2peak decreases in line with that of the lower body but, due to the lower peak values achieved during ACE, decreases in VO2peak may have more profound functional impact compared to that for the lower body. Using absolute and relative measures of VO2peak results in different age-related profiles when considered below 50 years of age. To further our understanding of whole body ageing more data is required for participants in mid and later life. The association between VO2peak and underlying physiological factors with age needs to be studied further, particularly in conjunction with activities of daily living and independent living.

Exploring the genetics underpinning dynamic laryngeal collapse associated with poll flexion in Norwegian-Swedish Coldblooded Trotter racehorses.

BACKGROUND: Dynamic laryngeal collapse (DLC) associated with poll flexion is the most common disorder of the upper respiratory tract (URT) in the Norwegian-Swedish Coldblooded Trotter (NSCT). The disorder, which has also been diagnosed in other breeds of trotters and gaited horses, appears to be related to anatomic phenotypes and only occurs during poll flexion when the horse is exercised 'on the bit'. OBJECTIVES: Identify genomic regions associated with DLC in the NSCT by combining a rigorous phenotyping protocol with genomic data from a high-density equine genotyping array. STUDY DESIGN: Prospective case/control study. METHODS: High-speed treadmill endoscopy was used to phenotype horses (n = 61) for DLC, distinguishing between cases and controls. Genome-wide association (GWA) analysis of DLC status was then performed using a principal component approach (PCA) with haplotype analyses subsequently performed for regions containing single-nucleotide polymorphisms (SNPs) above the suggestive genome-wide significance (GWS) threshold (P<1.0 × 10-5 ). RESULTS: One region containing 10 SNPs (Equus caballus chromosome [ECA] 7: 89,601,935-94,647,192) was above the suggestive GWS threshold. Two inferred haplotypes in this region demonstrated significant differences (P<0.001) between cases and controls, with the most frequent haplotype resulting in a significantly increased risk of DLC. MAIN LIMITATIONS: Small sample size as a result of stringent phenotyping protocols. CONCLUSIONS: The current study highlights a candidate genomic region on ECA7 as potentially important with regard to the manifestation of DLC. Further exploration of this region and the genes included within it will bring veterinarians and researchers closer to fully understanding the biological mechanisms underlying DLC in horses.

Magnetic resonance imaging findings in epileptic cats with a normal interictal neurological examination: 188 cases.

Epilepsy is a common neurological condition in dogs and cats. Although an increased likelihood of significant brain lesions with age has been identified in neurologically normal dogs with epileptic seizures, the underlying aetiology of epileptic seizures in cats that present with normal physical and neurological examinations remains unknown. In this cross-sectional study, the authors examined MRI findings in a large population of cats with a normal interictal physical and neurological examination. They hypothesised that age would have an impact on the prevalence of detectable lesions. First, following the guidelines for dogs and in accordance with previous studies, the authors divided the cats into three age groups (aged one year or younger, between one and six, and older than six) and calculated the proportion of cats with a detectable lesion on MRI in these groups. In the first group, 3/32 cats (9.4 per cent) had significant MRI abnormalities that were all consistent with congenital malformation; in the second group, only 5/92 (5.4 per cent) MRI scans were abnormal and in the third group, 15/ 65 (23.1 per cent) cats showed abnormal findings that were predominantly lesions of neoplastic origin. Second, to investigate the impact of age further, data were investigated as a continuous variable using receiver operating characteristic analysis. This indicated an optimal cut-off age of five years, above which MRI abnormalities were more likely, with an increase in the odds of a significant structural lesion increasing by 14 per cent per year.

Long-distance movement of phosphate starvation-responsive microRNAs in Arabidopsis.

Plant microRNAs are small RNAs that are important for genetic regulation of processes such as plant development or environmental responses. Specific microRNAs accumulate in the phloem during phosphate starvation, and may act as long-distance signalling molecules. We performed quantitative PCR on Arabidopsis hypocotyl micrograft tissues of wild-type and hen1-6 mutants to assess the mobility of several phosphate starvation-responsive microRNA species. In addition to the previously confirmed mobile species miR399d, the corresponding microRNA* (miR399d*) was identified for the first time as mobile between shoots and roots. Translocation by phosphate-responsive microRNAs miR827 and miR2111a between shoots and roots during phosphate starvation was evident, while their respective microRNA*s were not mobile. The results suggest that long-distance mobility of microRNA species is selective and can occur without the corresponding duplex strand. Movement of miR399d* and root-localised accumulation of miR2111a* opens the potential for persisting microRNA*s to be mobile and functional in novel pathways during phosphate starvation responses.

Examining age differences in duration of wage replacement by injury characteristics.

BACKGROUND: One explanation for why older age is associated with greater duration of wage replacement following a work-related injury may be that older workers sustain more severe injuries and different types of injury compared with their younger counterparts. AIMS: To examine the role of injury-related characteristics in explaining the impact of age on wage replacement duration, and whether the relationship between age and wage replacement duration is consistent across injury types and levels of severity. METHODS: A secondary analysis of workers' compensation claims in the Australian state of Victoria. In Victoria, only injuries which have accumulated >10 days of wage replacement, or have health care expenditures above a financial threshold, are eligible for compensation. Nested regression models were used to examine the relative contribution of injury-related characteristics to age differences in wage replacement duration. RESULTS: Older age was associated with greater days of wage replacement among men and women, even after adjusting for injury characteristics. Adjustment for differences in injury types and compensation reporting practices resulted in moderate attenuation of the age-duration relationship among men and small attenuation among women. The age-duration relationship was consistent across injury types/severity. CONCLUSIONS: The relationship between older age and greater duration of wage replacement is ubiquitous across injuries of different types and severity. Future research is required to understand better why older age is consistently associated with worse compensation outcomes following work-related injury.

Measurement of the (211)Pb half-life using recoil atoms from (219)Rn decay.

The radioactive half-life of (211)Pb was measured, by α-particle counting of samples of radiochemically pure (211)Pb in equilibrium with its α-emitting progeny, (211)Bi and (211)Po. The samples were prepared by the collection of (215)Po recoil atoms from the decay of the (219)Rn decay progeny produced from a (223)Ra sample onto stainless steel discs. The radioactive decay of the (211)Pb was measured utilising a 2π proportional counter operating on the α plateau. A half-life of 36.164 (13)min was determined, which is in agreement with currently available literature. A full uncertainty budget is presented. A recommended half-life of T1/2((211)Pb)=36.161 (17)min has been evaluated from the current literature values.

Cervical intervertebral foraminal disc extrusion in dogs: clinical presentation, MRI characteristics and outcome after medical management.

The aim of the present study was to retrospectively evaluate the clinical signs, MRI characteristics, interobserver agreement and outcome after medical treatment in dogs affected by cervical intervertebral foraminal disc extrusion (CIFDE). The medical records of three referral institutions were searched for dogs diagnosed with CIFDE between 2010 and 2012. Thirteen dogs were identified with CIFDE; affected dogs often had a normal neurological examination, with cervical hyperaesthesia and lameness as the most common clinical signs. On MRI, sagittal images showed no evidence of compression of the spinal cord; CIFDE could be identified only on transverse sections in all cases. An excellent interobserver agreement was found in the localisation of the affected intervertebral disc space, and a substantial agreement was found on the detection of CIFDE versus foraminal stenosis caused by overgrowing articular processes. All but two dogs recovered completely, and they were considered free of clinical signs without analgesia within a median of 7.5 weeks (range: 2-20) after medical management was started. The remaining two dogs were surgically treated followed by complete recovery. In view of our findings, the importance of a thorough MRI investigation in dogs presenting with cervical hyperaesthesia as the sole clinical sign should be highlighted.

Hypothalamic-anterior pituitary hormone deficiencies following traumatic brain injury in dogs.

Traumatic brain injury is an important cause of hypopituitarism in human beings, but limited information exists in the veterinary literature regarding this condition. The primary study objective was to investigate whether hypothalamic-anterior pituitary axis dysfunction exists following traumatic brain injury in 17 client owned dogs. In this retrospective, observational, open, cohort study, information about dogs presented to four separate referral centres between April 2008 and October 2013 was reviewed. Cases were included if they had suffered from non-fatal traumatic brain injury, resulting in neurological dysfunction, and follow-up evaluation included measurement of the serum concentration of insulin-like growth factor 1 (IGF-1), endogenous adrenocorticotrophic hormone (ACTH), basal cortisol, thyroid-stimulating hormone, total thyroxine (TT4) and, if appropriate, free thyroxine. Decreased IGF-1 concentration was the most common abnormality detected (7/17, 41 per cent; median 132 ng/ml, range <15-536), followed by a decreased TT4 concentration (4/17, 23 per cent; median 19, range 4-49). Basal cortisol concentration was less than 20 nmol/l in two cases (2/17, 12 per cent; median 65, range <20-1735), with concurrently undetectable ACTH (<5 pg/ml). This study demonstrates that dogs with a history of traumatic brain injury can develop endocrine abnormalities indicative of hypothalamic-anterior pituitary dysfunction.

Surgical treatment of dorsal hemivertebrae associated with kyphosis by spinal segmental stabilisation, with or without decompression.

This retrospective case series examined the effectiveness of spinal segmental stabilisation, with or without decompression, in nine dogs with neurological deficits associated with dorsal hemivertebrae. Data on signalment, preoperative neurological status, imaging findings, surgical techniques and outcome were evaluated. All cases occurred in young or adult, small-breed dogs with neurological signs ranging from progressive moderate pelvic limb ataxia to non-ambulatory paraparesis. Six dogs also showed urinary and faecal incontinence. In each dog, one or more dorsal thoracic hemivertebra(e) were detected by radiography and MRI. In all dogs, hemivertebra(e) were associated with kyphosis and reduced vertebral canal diameter. All dogs were surgically managed with spinal segmental stabilisation, using Steinmann pins and orthopaedic wires and/or sutures attached to the spinous processes. Three dogs also underwent additional decompressive surgery. Post-operative follow-up ranged from 1.5 to 5.5 years. Immediate or delayed post-operative complications occurred in three dogs, including implant migration or loosening. Eight dogs showed long-term gait improvement, with resolution of incontinence if previously present. At 2-6 years post-surgery, four dogs were neurologically normal, three had mild residual ataxia, one had moderate ambulatory paraparesis, and one dog relapsed 3.5 years after surgery, resulting in severe paraparesis. Spinal segmental stabilisation techniques, with or without decompression, can result in satisfactory outcomes in small dogs with hemivertebrae and mild to moderate neurological signs. Further adaptations might be required to avoid implant loosening and allow continued growth in immature dogs.

Age, occupational demands and the risk of serious work injury.

BACKGROUND: Interest in the relationship between age and serious work injury is increasing, given the ageing of the workforce in many industrialized economies. AIMS: To examine if the relationship between age and risk of serious musculoskeletal injury differs when the physical demands of work are higher from those when they are lower. METHODS: A secondary analysis of workers' compensation claims in the State of Victoria, Australia, combined with estimates of the insured labour force. We focused on musculoskeletal claims, which required 10 days of absence or health care expenditures beyond a pecuniary threshold. Regression models examined the relationship between age and claim-risk across workers with different occupational demands, as well as the relationship between occupational demands and musculoskeletal claim-risk across different age groups. RESULTS: Older age and greater physical demands at work were associated with an increased risk of musculoskeletal claims. In models stratified by occupational demands, we observed the relationship between age and claim-risk was steeper when occupational demands were higher. We also observed that the relationship between occupational demands and risk of work injury claim peaked among workers aged 25-44, attenuating among those aged 45 and older. CONCLUSIONS: This study's results suggest that although older workers and occupations with higher demands should be the targets of primary preventive efforts related to serious musculoskeletal injuries, there may also be gains in targeting middle-aged workers in the most physically demanding occupations.

Corpus callosal abnormalities in dogs.

BACKGROUND: Corpus callosal abnormalities (CCA) in dogs have been only sporadically reported and are poorly characterized. HYPOTHESIS/OBJECTIVES: To describe the clinical presentation and magnetic resonance imaging (MRI) characteristics of dogs with CCA. ANIMALS: Fifteen client-owned dogs. METHODS: Retrospective study. Records of the contributing institutions were reviewed to identify dogs diagnosed with malformations affecting the corpus callosum (CC); cases in which the CCA was thought to be secondary were excluded. RESULTS: The most represented breeds were Staffordshire Bull Terriers (5/15) and Miniature Schnauzers (3/15; n = 3, 20%) and the mean age at time of presentation of 19 months (range 3-81 months). The clinical signs most commonly reported were adipsia/hypodipsia with associated hypernatremia (12/15), tremors (6/15), and seizures (6/15). Review of the MR images revealed that 10 dogs had absence of the rostral CC and hypoplasia of the caudal portion, 4 dogs had a diffusely hypoplastic and dysplastic CC, and 1 dog had a diffusely hypoplastic CC. In 14 cases, there was abnormal cortical development with fusion of the ventral frontal lobes and part of the diencephalon, indicating lobar holoprosencephaly. CONCLUSIONS AND CLINICAL IMPORTANCE: Previous literature has mainly associated CCA with adipsia and only 12 of 15 dogs in the current series demonstrated this abnormality. There are different degrees of the malformation but in 10 dogs the rostral portion of the CC is most severely affected. Fourteen dogs have simultaneous fusion of the midline structures rostral to the CC; this region has several structures involved in thirst regulation and might explain this derangement.

Meningoencephalitis of unknown origin: investigation of prognostic factors and outcome using a standard treatment protocol.

Meningoencephalitis of unknown origin (MUO) is a common inflammatory CNS disease in dogs, with a variable and unpredictable outcome. MRI and cerebrospinal fluid (CSF) features were prospectively evaluated to establish their utility as prognostic markers for predicting mortality, relapse and long-term outcome in 39 dogs with MUO. MRI and CSF analysis were performed at initial diagnosis and three months into treatment with prednisolone and cytosine arabinoside. When possible, MRI was repeated every 12 months thereafter. Median survival time was 26 days. All deaths occurred within 52 days of diagnosis (22/39; 56 per cent). One-third (13/39) died within 72 hours of diagnosis. Outcome was good or excellent in 12/17 surviving dogs. Loss of the cerebral sulci and foramen magnum herniation on MRI were associated with increased risk of mortality. An abnormal CSF analysis at the three-month re-examination was associated with increased risk of relapse (P=0.04). The combination of MRI and CSF analysis provided a greater sensitivity for predicting relapse than one modality alone. Discontinuing treatment before MRI lesions resolved always resulted in relapse. The presence of certain MRI characteristics may indicate an increased risk of mortality. Dogs alive three months following diagnosis have a very low risk of death due to MUO.

Sensitivity and specificity of MRI for detecting facial nerve abnormalities in dogs with facial neuropathy.

Idiopathic facial neuropathy in dogs is conventionally diagnosed by exclusion of structural and metabolic causes of a single cranial neuropathy. To investigate the reliability and validity of MRI for supporting a diagnosis of facial neuropathy in dogs, we examined MR images of the brainstem from 20 dogs with presumed idiopathic facial neuropathy, and 20 control dogs. Two different types of MRI sequence were compared: volumetric interpolated breath-hold examination MRI (VIBE-MRI), and conventional T1-weighted MRI. Three independent observers, blinded to the case details, were presented with VIBE-MR images in a random order, and were required to indicate the presence of hyperintensity of the facial nerve following intravenous contrast administration. The vestibulocochlear nerve was also assessed, and the whole process was repeated for conventional post-contrast T1-weighted images. Following contrast administration, the sensitivity of VIBE-MRI for detecting facial nerve abnormalities ranged from 86 per cent to 96 per cent, and the specificity from 87 per cent to 92 per cent; conventional T1-weighted images yielded a sensitivity of only 39 per cent - 65 per cent, and a specificity of 94 per cent - 96 per cent. MRI was not a sensitive detector of vestibulocochlear nerve abnormalities in 14 dogs with concurrent vestibular dysfunction. This study shows that VIBE-MRI is a robust technique for confirming presumed idiopathic facial neuropathy in dogs, and suggests an inflammatory component to this condition in a high proportion of dogs.

The psychosocial work environment and incident diabetes in Ontario, Canada.

BACKGROUND: Relatively few longitudinal studies have explored the relationship between psychosocial work conditions and diabetes incidence. Given the increasing global burden of diabetes this is an important area for public health research. AIMS: To examine the relationships between dimensions of the psychosocial work environment on the subsequent incidence of diabetes among men and women in Ontario, Canada over a 9 year period. METHODS: We used data from Ontario respondents (35 to 60 years of age) to the 2000-01 Canadian Community Health Survey linked to the Ontario Health Insurance Plan database for physician services and the Canadian Institute for Health Information Discharge Abstract Database for hospital admissions. Our sample of actively employed labour market participants with no previous diagnoses for diabetes was followed for a 9 year period to ascertain incident diabetes. RESULTS: There were 7443 participants. Low levels of job control were associated with an increased risk of diabetes among women, but not among men. Counter to our hypotheses high levels of social support were also associated with increased diabetes risk among women, but not among men. No relationship was found between any psychosocial work measure and risk of diabetes among men. CONCLUSIONS: Given the increasing prevalence of diabetes worldwide, job control could potentially be an import ant modifiable risk factor to reduce the incidence of diabetes among female, but not among male, workers. More research is needed to understand the pathways through which low social support may protect against the development of diabetes.

No effect of intravenous Actovegin® on peak aerobic capacity.

There is much speculation that Actovegin® is ergogenic, but no scientific work has been published in this field. 8 participants [mean(± SD) age, height and mass of 24 (7) years, 1.76 (0.07) m and 80.1 (9.1) kg, respectively] completed 3 exhaustive arm crank ergometry tests. Following Baseline testing 2 further tests were performed 2 h following the injection of either 40 ml of Actovegin® or a saline Placebo. Peak power (Wpeak), peak physiological responses, concentrations of blood glucose and lactate, exercise efficiency (%), VO2 gain (ml·W-1), and the respiratory compensation point (RCP) were determined. Repeated measures ANOVA tests were used to analyse data with significance accepted at p≤0.05. Values of mean (±90% CI) bias were calculated to further explore quantitative differences between trials. Strong trends for variations in Wpeak (p=0.054) and RCP (p=0.054) were evident; likely meaningful effects existed between the Baseline and both injection trials, but only a trivial effect was noted between Placebo and Actovegin® (bias: Wpeak 0.8±3.2 and RCP; 2.5±4.7 W). Concentrations of blood lactate and glucose changed across time, but did not differ between the 3 trials. Our data suggests the Actovegin® is not ergogenic and did not influence functional capacity in the context of the exhaustive, upper-body test employed.

Cardiovascular actions of leptin in the subfornical organ are abolished by diet-induced obesity.

The subfornical organ (SFO), a sensory circumventricular organ lacking the normal blood-brain barrier with well documented roles in cardiovascular regulation, has recently been identified as a potential site at which the adipokine, leptin, may act to influence central autonomic pathways. Systemic and central leptin administration has been shown to increase blood pressure and it has been suggested that selective leptin resistance contributes to obesity-related hypertension. Given the relationship between obesity and hypertension, the present study aimed to investigate the cardiovascular consequences of the direct administration of leptin into the SFO of young lean rats and in the diet-induced obesity (DIO) rat model, which has been shown to be leptin-resistant. Leptin administration (500 fmol) directly into the SFO of young rats resulted in rapid decreases in blood pressure (BP) [mean area under the curve (AUC) = -677.8 ± 167.1 mmHg*s; n = 9], without an effect on heart rate (mean AUC = -21.2 ± 13.4 beats; n = 9), and these effects were found to be dose-related as microinjection of 5 pmol of leptin into the SFO had a larger effect on BP (mean AUC = -972.3 ± 280.1 mmHg*s; n = 4). These BP effects were also shown to be site-specific as microinjection of leptin into non-SFO regions or into the ventricle was without effect on BP (non-SFO: mean AUC = -22.4 ± 55.3 mmHg*s; n = 4; ventricle: mean AUC = 194.0 ± 173.0 mmHg*s; n = 6). By contrast, microinjection of leptin into leptin-resistant DIO rats was without effect on BP (mean AUC = 205.2 ± 75.1 mmHg*s; n = 4). These observations suggest that the SFO may be an important relay centre through which leptin, in normal weight, leptin responsive rats, acts to maintain BP within normal physiological limits through descending autonomic pathways involved in cardiovascular control and that, in obese, leptin-resistant, rats leptin no longer influences SFO neurones, resulting in an elevated BP, thus contributing to obesity-related hypertension.